Isogenic cotton lines for glabrous or smooth and hairy were compared in greenhouse studies. Potato leafhopper nymphs were used to infest plants of two ages. The node of first square and the number of squares at first bloom were used to compare hairy and smooth plants and with non-infested check plants. There was no difference in the node of first square. Total number of squares at first bloom was reduced an average of 10% when infested for 3 days with 4 nymphs at the first or second true leaf.